The present invention relates to a process for the preparation of a flavouring composition.
In U.S. Pat. No. 4,571,342 there is described a process for the preparation of a flavouring composition with a charcoal broiled flavour which is prepared by subjecting a film of fat or oil to a temperature within the range of from 285.degree. C. to 475.degree. C. in the presence of oxygen for a period of time effective to develop a charcoal broiled flavour and collecting the resultant fat or oil.
We have now found, surprisingly, that individual fatty acids or mixtures thereof, when subjected in the presence of oxygen to temperatures similar to those used in the process described in U.S. Pat. No. 4,571,342 produce flavouring compositions with characteristics specific to each individual fatty acid or mixture, these flavouring compositions being obtained not only from the treated fatty acid starting material but also from the volatile distillates formed during the treatment.
Accordingly, the present invention provides a process for the preparation of a flavouring composition which comprises subjecting a fatty acid or any mixture of two or more fatty acids to a temperature from 150.degree. C. to 475.degree. C. in the presence of oxygen and collecting the resultant treated fatty acid or the volatiles distilled therefrom.
The fatty acids employed may be saturated or unsaturated, may contain from 6 to 30 carbon atoms, preferably from 10 to 27 and especially from 16 to 24 carbon atoms. They may, for instance, be obtained from any edible triglyceride fat or oil by enzymatic, chemical or high temperature/pressure hydrolyses. Examples of suitable oils from which fatty acids may be obtained include safflower, linseed, blackcurrant seed and grapeseed oils which are naturally rich in linoleic acid (64-78%), and olive oil, low erucic acid rapeseed oil and high oleic safflower oils which are naturally rich in oleic acid.
Fatty acids suitable for employment in the present invention include, for example, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid which may be used individually or as mixtures. Particular fatty acid mixtures which are also suitable include butter acids, dairy acids, cheese acids, enzyme hydrolysed vegetable oils such as olive oil or coconut oil and enzyme hydrolysed animal fats. It is also possible to use a fatty acid which has been oxidised (.i.e., rancidified), e.g. 10-hydroperoxylinoleic acid.
In addition, the fatty acids can advantageously be used in admixture with certain triglycerides e.g. a mixture of beef fat and oleic acid, for instance, in a ratio of from 2:1 to 4:1 and a mixture of chicken fat and linoleic acid, for instance, in a ratio of from 2:1 to 6:1.
Moreover, if desired, flavour precursors may be added to the fatty acid prior to the heat treatment to enhance the flavour, e.g., sulphur containing compounds such as cysteine, cystine, methionine, thiamine, hydrogen sulphide, or sulphur containing extract from vegetables such as onions, garlic or members of the "Brassica" family.
Preferably, the temperature to which the fatty acids or mixtures thereof are subjected is from 250.degree. C. to 400.degree. C. and especially from 285.degree. C. to 350.degree. C. The time of the treatment may be from a few seconds to several hours, more usually from 1 minute to 6 hours, and preferably from about 5 minutes to 4 hours. The actual period of time chosen may be the time effective to produce the desired flavour note, longer periods generally producing more smoked or charcoal cooked notes.
The flavourants created by the process of the present invention depend on the fatty acid material employed. For example, oleic acid or a mixture of fatty acids containing predominantly oleic acid have a strong beef-like character while linoleic acid or a mixture of fatty acids containing predominantly linoleic acid have a strong roasted chicken or fish character.
Several types of apparatus may be used for the preparation of the flavourant. For example, a thin film reactor similar to that used in U.S. Pat. No. 4,571,342 may be employed and such apparatus would also include pipe reactors, etc., where a thin film of the fatty acid material is passed down the sides of a heated pipe while air or oxygen is passed through the pipe. When such an apparatus is used, the fatty acid material that passes through the pipe is collected and used as the flavourant. However, in the present invention the use of a bomb-type apparatus is especially advantageous because by using such an apparatus not only can the treated fatty acid material be used as a flavourant but also the volatiles distilled or carried by the air flow out of the reactor can be collected and used as a flavourant. In addition, distillates offer the advantage of fractionating the volatiles with time to produce a broader range of flavourants, each having a different flavour, which can be used either individually or in combination with other fractions to obtain an even broader range of flavourants. Moreover, there is usually a significant amount of water distilled over with the volatiles generated in a bomb-type apparatus and if this water is separated from the volatiles, it can also be used as a flavourant. Thus, by varying the initial fatty acid material employed, the reaction temperature, the intervals of time used for collecting the volatiles and the specific combinations of the fractions, a myriad number of flavour notes can be generated from a single fatty acid. In addition, two or more fractions obtained from different processes according to this invention may be used as flavourants.
By the process of the present invention, flavours can be obtained which can be specifically targeted towards a wide variety of meats, chicken, fish or cheese depending on the starting fatty acid material employed, the temperature used and, if a bomb-type apparatus is used, the specific times that the volatile fractions are taken, as well as the combinations of the fractions.
The oxygen present in the treatment is conveniently obtained from air, and the quantity required depends on the method employed to produce the flavourant. Generally the air is passed through the fatty acid material at a rate of from 1 to 5000 ml/min per 100 g fatty acid material. However, within this range, when a pipe reactor is used, a small amount of air is generally satisfactory, e.g., between 0 and 100 ml/min per 100 g fatty acid material, especially when the flavourant is the recovered treated fatty acid material. When a bomb-type apparatus is used, the air is preferably passed through at a rate of from 10 to 3000 ml/min and especially from 15 to 2500 ml/min per 100 g fatty acid material.
The flavouring composition produced by the process of the present invention may be used in the powdered form which may be obtained by spray drying in admixture with carriers which can encapsulate the flavouring composition, e.g., gum arabic, malto-dextrin modified, food starches, dextrins or a protein such as gelatin. Advantageously, a solution or an emulsion of the flavouring composition and carrier is formed which is dried, for example, by spray-drying. The amount of flavouring composition present is usually from 5% to 50% and preferably from 15% to 30% by weight based on the total weight of the flavouring composition and the carrier.
The flavouring composition can be used by itself, dispersed in a fat, or in admixture with a carrier, for incorporation into, or coating onto a wide variety of foodstuffs to impart the specific flavour e.g. meats, sauces, soups, etc.
The present invention will now be further illustrated by way of example with reference to the accompanying drawing.